I might be late to the party, but I recently got Multiwinia and was wondering if any modding tools was created, or a way to see source code; thank you to anyone who responds!

EDIT:

so correct me if I'm wrong,

after a first look at the files contained in main.dat, I see that in the folder "Shapes" are the (supposedly) models of game's units, with a .shp extension; such extension is built in...what? Python shapefile?

There aren't really any modding tools per se, though the Darwinia modding environment can be used to construct maps for Multiwinia. That being said, the source code can be purchased from the IV store (the Darwinia and Multiwinia source code can be purchased as a package for $45), so anything that you want to do is, in theory, doable.

As to the shape files, I have no idea what program the format is meant to work with, though someone has put together a script to import Blender files.[1] Honestly, the Darwinia modding forum probably has lots of useful resources. I wouldn't expect anyone to be of much help there (most of us haven't actually done any modding in years), but there are a lot of old topics that might be useful.